DHAKA, Bangladesh — Police in Bangladesh fired at protesters and opposition activists torched more than 100 polling stations Sunday during a national election boycotted by the opposition and described as flawed by the international community. At least 18 people were killed in election-related violence.

Prime Minister Sheikh Hasina’s refusal to heed opposition demands to step down and appoint a neutral caretaker to oversee the election led to the boycott, undermining the legitimacy of the vote, which is all but certain to return Hasina to power.

Opposition activists have staged attacks, strikes and transportation blockades in unrest that has left at least 293 people dead since last year.

Voter turnout appeared low. In a statement, opposition spokesman Mirza Fakhrul Islam Alamgir praised Bangladeshis for “rejecting this meaningless” election.

Vote counting began after polls closed Sunday. Official results are expected Monday morning.

The opposition announced a 48-hour general strike starting Monday to demand that the election results be voided.